1. Field of the Invention
The present invention relates to a digital multimedia broadcasting (DMB) receiver, and more particularly, to a method for controlling partial image enlargement in a DMB receiver making it possible to enlarge a partial image selected by a user out of a broadcast image and to display the enlarged partial image.
2. Description of the Related Art
Recently, standardization and commercialization of a digital audio broadcast is being globally promoted. Europe adopts Eureka-147 as a digital audio broadcast standard and uses a digital audio broadcasting (DAB) system, America uses a digital audio radio (DAR) system, Canada uses a digital radio broadcasting (DRB) system, the international telecommunication union-radio communication sector (ITU-R) uses a digital sound broadcasting (DSB) system and Korea adopts and uses a digital multimedia broadcasting (DMB) system.
The DAB system has been developed as the next-generation broadcasting system. The DAB system is robust against radio environments and noises in the downtown, and thus makes it possible to receive CD-quality audio signals in a vehicle driving at a high speed although broadcasting signals are transmitted at low output power. Also, the DAB system has expanded the existing audio radio broadcasting concept into an audio/video radio broadcasting concept, and makes it possible to transmit various multimedia information such as news, traffic information, weather information, geographic position information and motion picture information by character and graphic, in addition to a music broadcast.
In the meantime, the DMB system also has been developed as the next-generation broadcasting system. With digitalization of audio broadcasting, the DMB system exceeds the existing AM/FM radio broadcasting system and makes it possible to transmit CD-quality audio signals, characters or graphics and motion pictures at 1.5 Mbit/s, thereby enabling various data services, a bidirectional broadcasting service and a superior mobile reception quality
The DMB service can be broadly divided into a terrestrial DMB service and a satellite DMB service according to its transmission medium types, and the satellite DMB service can be subdivided into a stationary satellite DMB service and a mobile satellite DMB service
The European broadcasting union (EBU) and the ITU-R have recommended the required characteristics of the DMB system as follows:
1. The DMB system should be realized by a digital transmission scheme guaranteeing a high broadcast quality, should be continuously acceptable during the next 50 years, and should provide a high-quality sound of 2 or more channels.
2. The DMB system should make it possible to errorlessly receive a broadcast signal also by a portable terminal in a driving vehicle That is, the DMB system should enables mobile reception, portable reception and stationary reception.
3. The DMB system should make it possible to provide a PAD (program associated data) channel service for transmitting additional data by a normal broadcast program and a Non-PAD channel service for an independent broadcast program. Accordingly, the DMB system should be able to recognize radio signal data, character data and program data.
4. The DMB system should be high in its transmission capacity and efficiency so as to be able to accommodate various data channel capacities and to increase frequency usage efficiency.
A DMB receiver for the DMB system is also being commercialized. For example, a DMB receiver built in a portable terminal, such as a personal digital assistant (PDA), or a vehicle terminal has been already launched.
Also in the DMB system, a CODEC (coder and decoder) of a DMB receiver decodes a received broadcast image signal into a screen image standardized according to a display screen size. That is, if image data constituting one screen image is 320×240 in its size, the image data is displayed through an image display device such as a liquid crystal display (LCD) or a cathode ray tube (CRT) in such a way that a received source image is displayed as it is received in the DMB receiver.
However, there has been no method capable of enlarging a desired partial image out of a source image (i.e., broadcast signals) received in real time and displaying the enlarged partial image.